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Патент USA US2403929

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July 16, 1946.
2,403,929
cgs, KUHN, JR
CATALYTIC REFORMING PROCESS
Filed Aug. 22, 194g
2 sneaks-sheet 1
.
By
`
INI/¿-N TOR
â. WJ
ATTORNEY
2,403,929
Patented July 16, 1946
UNITED STATES PATENT GFFICE
2,403,929
C_ATALYTIC REFORMîNG PROCESS
Carl S. Kuhn, Jr., Dallas, Tex., assìgnor to Socony
Vacuum Oil Company, Incorporated, New York,
N. Y., a corporation of New York
Application August 22, 1942, Serial No. 455,775
2 Claims.
l
This invention relates to the catalytic rear
rangement or reforming of branched-chain hy
drocarbons and is especially concerned with the
manufacture of complete aviation gasolines using
relatively narrow-boiling fractions of such hydro
(Cl. 260--683.4)
>`arrangement to yield a mixture of branched
chain hydrocarbons which boils over a relatively
wide range, Another object is to afford a process
for treating a relatively narrow-boiling fraction
carbons.
It is well known that in order to insure proper
carburetion and combustion of motor fuel, the
of alkylate gasoline or similar gasoline, consist
ing essentially of branched-chain hydrocarbons
in order to yield a complete aviation gasoline of
not substantially less octane value. Still another
so as to promote a molecular conversion or rear
.5,5 liquid phase and therefore sufficient pressure is
object is to provide a process for synthesizing a
distribution of hydrocarbons in the gasoline boil
ing range should be uniform, A preponderance 10 complete aviation gasoline from gaseous hydro
carbons. These and other objects will be appar
of either light or heavy material leads to uneven
ent from the following description of my inven
`carburetion‘and uneven burning, This is recog
tion.
nized by users, and this recognition is reflected in
My invention is based upon the discovery that
purchasing specifications which require reason
if a relatively narrow-boiling fraction of gasoline
able distribution of material across the entire
boiling, branched-chain hydrocarbons is treated
boiling range of the fuel. Such requirement is
in the presence of an alkylation catalyst under
usually arrived at by specifying that the product
alkylating conditions of temperature and pressure
be such that only given percents of it shall dis- f
for a, controlled period of time, a gasoline frac
till over at each of several given `temperatures in
20 tion having desired distillation characteristics
the boiling range.
may be produced therefrom. If desired, the
During recent years production of high octane
narrow-boiling fraction may be reformed to pro
value gasolines by synthesis from lighter hydro
duce a complete aviation gasoline having the
carbons has assumed increasing importance an-d
proper distillation characteristics. Moreover, the
widespread usage. Thus, for example, in proc
esses known to the art, high octane gasolines 25 gasoline-boiling product formed by my process
possesses substantially as high an octane rating
may be prepared by alkylating normally gaseous
as that of the original narrow-boiling, branched
isoparaiiins with normally gaseous oleñns in the
chain hydrocarbon fraction.
presence of such catalysts as sulfuric acid, phos
In general, the conditions under which the
phoric acid, aluminum chloride, etc. Likewise, in
alkylation catalysts reform alkylate or other
my copending application S. N, 320,097, ñled Feb
narrow-boiling hydrocarbons are essentially the
ruary 2l, 1940, there is disclosed a similar alkylat
same as those under which they will produce
ing process using hydrogen fluoride as a catalyst.
alkylate from lighter paraiiins and olefins, ex
Branched-chain hydrocarbons of high octane
cept that sufñcient additional reaction time must
value are prepared also by polymerization of gase
be provided to obtain a reformed product of the
ous oleñns, and the polymers are usually hydro
desired characteristics, Thus, for example, when
-genated to give a saturated product.
a catalyst consisting essentially of hydrogen fluo
Since alkylation processes, as usually con
ride is used, the hydrogen fluoride should be of
ducted, eiîect predominantly the condensation of
at least about 90% concentration, and a tempera
one particular isoparafñn with one particular
ture preferably between about -lO and about
olefin, the resulting alkylate gasoline, although of
+30° C. should be employed. It is to be under
high octane value, is composed essentially of
stood, however, that since hydrofluoric acid, un
branched-chain isomers of one parafflnic hydro
like sulfurie acid, is not an oxidizing acid, rather
carbon. Therefore, the alkylate is of relatively
high temperatures up to about 200° C. may be
narrow-boiling range, or, at least, it does not have
a. required uniform distribution of hydrocarbons 45 used if desired. Since it is generally preferable
to operate with the hydrocarbons in the liquid
across the desired gasoline-boiling range. This
phase, the critical temperature of the hydrocar
is one of the reasons why alkylate gasoline is now
bon being reformed will frequently set the upper
conventionally blended with gasoline of inferior
temperature limit for liquid phase operation.
anti-knock value in order to form blended gaso
line of proper distillation characteristics and va 50 The alkylating conditions for such catalysts as
sulfuric acid, aluminum chloride, etc., are well
por pressure.
known.
Accordingly, it is an object of this invention to
As stated previously, the reforming reaction is
provide a process for treating a relatively narrow
preferably carried out with the reactants in the
boiling fraction of branched-chain hydrocarbons
eficaces
3
used to maintain the reactants in this liquid
phase. Suitable agitating means should be pro
vided in order to afford efficient contacting of
the hydrocarbons and the catalyst as is custom
ary in the alkylation art. Liquid phase opera
tion is not essential, however, and lower pressures
may be used if desired.
The relative proportions of the catalyst to the
4 .
the heptanes formed by the alkylation of iso
butane with propylene. It is my belief, although
my invention should not be limited to any par
ticular theoretical considerations that under a
given set of reaction conditions, the reaction
time is primarily dependent upon the configura
tion of the carbon atoms in the charge stock4
This discussion of reaction time is directed to
batch operation.
Continuous processing, of
alkylation processes. Within certain limits, in 10 course, permits the use of much shorter con
creasing the amount of catalyst increases the
tact times as is well understood in the art.
It is difîìcult to state definitely which catalyst
amount of reforming obtained in a given time.
total hydrocarbons are similar to those used in
In the case of solid or immiscible liquid catalysts,
and to a certain extent with a soluble catalyst,
increased agitation increases the amount of re
forming obtained in a deñnite time period since
the agitation produces better contact between
the catalyst and hydrocarbons.
Alkylation reactions are generally carried out
or catalysts will effect the desired amount of
reforming in the shortest period of time, since
this also varies with charge stockA and the re
action conditions. I have found, however, that
with certain alkylates one catalyst is preferable,
while with other alkylates another catalyst will
be preferred. For example, the heptanes formed
in the presence of a large excess of isoparañìns. 20 Iby the alkylation of isopentane with ethylene
In this respect, as well as in the reaction time,
the reforming reaction is different. The amount
will be reformed most effectively with alumi
num chloride, While the heptanes formed by the
' of excess isoparaiiin over that required to com
alkylation of isobutane with propylene will be
reformed by hydrogen fluoride substantially as
bine with the oleñn is generally of the order of
upwards of 460 mol percent in the case of alkyl 25 rapidly as with aluminum chloride. For the
most part it may be stated that those alkylation
ation reactions. In contrast thereto, reforming
catalysts which are most effective for the forma
reactions will proceed most rapidly in the ab
sence of additional isoparaihnic hydrocarbons,
tion of a particular alkylate are most effective
although limited amounts of light isoparafiins or
for its catalytic rearrangement.
Aluminum chloride and hydrofluoric acid have
high-boiling, saturated hydrocarbons up to not 30
been mentioned above as typical catalysts suit
over` 100 to 200 mol percent of the hydrocarbon
able fcr my reforming process. It is to be un
being reformed, may be present as will be dis
derstood that any hydrocarbon alkylation cat
cussed more in detail later in the description of
alyst is likewise suitable. The various catalysts
my invention.
rI‘he exact reaction time for each individual 35 must, of course, be used under conditions of tem
reforming operation» must be worked out by a
perature, pressure, concentration, etc., at which
consideration of several factors. Thus the re
forming time factor is dependent upon the par
ticular alkylate or other isoparañinic hydrocar
they are effective as alkylation catalysts. rThe
following are illustrative of alkylation catalysts
which are particularly useful in my process: hy
bon stock being reformed, the catalyst, the ratio 40 drogen fluoride, sulfuric acid, aluminum chlo
of catalyst to hydrocarbons, the efficiency of con
ride, aluminum bromide, and boron trifluoride.
tact between catalyst and hydrocarbons, the tem
My invention is not, however, to be construed as
limited to the use of the aforementioned cata
perature, the speciñcation characteristics de
sired in the reformed product, etc. Although the 45 lysts. In general, aluminum chloride represents
the preferred catalyst for use with the less
reaction may be speeded up by increasing the
highly branched-chain paranins, whereas hy
temperature, increase in the temperature will in
drogen fluoride represents the preferred catalyst
some cases produce an increase in the amount
for use with the more highly branched-chain
of side reactions such as polymerization of any
Aluminum . .bromide
corresponds
oleñns formed as intermediate products in the 50 paraflins.
reforming reaction. Accordingly, even with
rather closely to aluminum chloride, While sul
non-oxidizing catalysts, the temperature is gen
furic acid more nearly resembles hydrogen fluo
ride in its catalytic reforming properties.
erally kept below about 80 to 90° C. kIn general
I am aware that some of the alkylation cata
the reaction time used in carrying out the de
sired amount of rearrangement will vary 'be 55 lysts will isomerize normal paraiîinic hydrocar
bons to produce branched-chain parafûnic hydro
tween about 1 and 24 hours. For a given set
carbons. For example, Nenitzescu and Dragen
of conditions of temperature, catalyst concentra
have disclosed that aluminum chloride will iso
tion, etc., one of the most important factors in
merize normal hexane and normal heptane to
determining the amount of time required for a
particular reforming operation is the particular 60 produce branched-chain hexanes and heptanes
(of. Berichte, 66 B, 1892 (1933)). The iso
charge stock being subjected to the process.
merization of normal parafûns to corresponding
The charge stocks of primary concern for re
branched-chain hydrocarbons by aluminum bro
forming are the various octane and heptane al
mide has been demonstrated by Glazebrook, Phil
kylates, and the range of reaction times given is
generally suitable for these alkylates. With some 65 lips and Lovell (cf. J. Am. Chem. Soc. 58, 1944
(1936)). Where these isomerization processes
of the hexanes, nonanes or decanes the range
are applied to the gasoline-boiling normal paraf
of reaction time is usually greater than the
range given above, particularly where alkyla
fins, there will be concurrent isomerization,
cracking of the normal parañìns to low boiling
tion catalysts less effective for the particular al
kylate are used. The time required for reform 70 normal paran-ins, and reforming of the isomers
ing also varies with the particular alkylate isom
produced. The isomerization of normal paraiîlns
ers being treated. For example, the heptanes
is usually extremely slow under the comparative
formed by the alkylation of isopentane with
ly mild conditions used for reforming the
ethylene are considerably slower in reforming 'to
branched-chain paraflins. The boiling charac
a uniformly boiling hydrocarbon mixture, than 75 terìstics of the product from such a` combined
2,403,929
,
6
5
Hydrocarbon soluble catalysts‘suc‘h as alumi
processV isv not controllable-within ythe meaning
num bromide, possess the advantage that molec
ular contact is obtained between catalyst and hy
withV which this term is used in‘my invention.
The 'concurrent -isomerization and reforming' of
gasoline-boiling, normal parafûns is not included
within my invention. However, fractionation of
drocarbon, hence a minimum of agitation is re
such a hydrocarbon mixture to separate out a
quired. The catalyst may be'subsequently re
moved from thehydrocarbons by chilling, which
narrow-boiling, branched-chain paraffin would
will cause the catalyst to separate out as a solid,
yield a distillate fraction suitable for treatment
by my process to form a~hydrocarbon mixture
of "desired distillation characteristics within the
gasoline range. `Therefore, the reforming of. a
narrow-boiling,` branched-chain isoparaffin ob
or by distillation of the hydrocarbonsfrom the
catalyst, preferably at reduced pressures.`
10
_and this not only serves to produce contactbe
35
Because the reaction involved in my reforming
process is of suiiîcient intensity to produce hy
drocarbons boiling over the entire gasoline range,
therealso are produced smaller amounts of satu
tainedin this> way, as well as from any other
rated hydrocarbons boiling over and‘below the
source, is to be considered as included within
the scope of my invention.
~
,
15 gasoline range. In this connection, I have found
that these less valuable saturated portions> vof
The catalysts used in my process are both hy
the reformed product distilling outside the gaso
drocarbon soluble and hydrocarbon insoluble cata
line range, e. g., below 25° C. and above 168°. C.,
lysts. Aluminum bromide is a typicalv hydrocar
can be utilized for the production of additional
bon soluble catalyst. The. hydrocarbon immisci
ble catalysts are further capable of division. into 20 gasoline-boiling hydrocarbons by reacting these
products together in the presence of essentially
three groups based upon their physical properties
anhydrous hydrogen fluoride, or other alkylating
under the reaction Aconditions as follows: solid,
catalyst. It should be noted that this reaction
immiscible catalysts, typiñed by-aluminum chlo
is not alkylation since both reactants are satu
ride; liquid, immiscible catalysts, typìñedby sul
.
furic acid and hydroiiuoric acid; yand gaseous 25 rated hydrocarbons.
Another feature of my invention is based >upon
catalysts, typiñed by gaseous hydrogen iiuOride.
my discovery that the distillation characteristics
Because of the different physicalcharacteristics
of the ñnal product may be influencedby. the
ofv the various catalystsused, certain- „differences
addition of minor amounts of either light isopar
exist in the operating procedures followed in the
carrying out-of my invention.V The ¿essentialfea 30 aûins such as isobutane or isopentane, or bythe
addition of hydrocarbons boilingV above the gaso
tures ofrthelinvention arethe same, regardless
line range. The amount of this added hydrocar
of the particular type of catalyst selected.
bon `should be preferably less th-an an equimolar
, _The gaseous catalysts may simply be bubbled
quantity, and is of the general order` of from V5 to
>up through « the hydrocarbon inoI packed tower,
about, 40 mol percent of .the alkylate charge
stock. Since these light and heavy hydrocarbons
are end products of the reforming reaction, their
presence in the reaction mixture has the effect,
sary agitation. b flîhé catalyst, is _very easilyre
also, of slowing down the reforming reaction.
`_circulateol for recontacting withhthe same batch
of hydrocarbons,V or ,» with a fresh hydrocarbon 40 Obviously, if too great a quantity of` these high
and low boiling materials are present in the mix
fory treatment.¿ HContinuous operation _is very
ture, the desired catalytic rearrangement will be
easily performed. `Ön a yolumetric basis, the
largely suppressed. As a general practice neither
-quantity of catalyst used is` fairly substantial
tween hydrocarbon and catalyst, but WilLUin‘a
properly designed reactor, produce _all'th'e fneces
of these added hydrocarbons should be present
relative _tothe Aquantity of hydrocarbon being
reformed, thus requiring, in general,~ more costly
in an amount much in excess of an equimolar
quantity of the branched-chain hydrocarbon be
ing reformed. As mentioned previously, the
catalysts differ appreciably in their activity.
`equipment than with the other typev catalysts.>
Solid, iinmiscible catalysts, such as aluminum
f >v"'c'zhlo‘rida;possessthe advantage VthatV bulk separa
tion ofthe liquid gasoline produced fróm-'theÍs‘olid
catalyst. is Very`simple. Considerable >agitation to”
hydrocarbons added or recirculated should be less
is required with catalysts'Y of this type «_to‘obtain
than about an equimolar quantity (based upon
elücient "contacting Moreover, the ‘ >all'irninum
the hydrocarbons being reformed), and prefer
chloride reacts with someof'the hydrocarbons
„to >forni" al sludge, Viizhose regeneration' involves
considerable additional processing.
'
`
Immiscible liquid catalysts such‘as sulfuric‘acid
and hydr'o'iluoric acid also possess the’advant'age
that bulk separation of product from the catalyst
involves a mere settling operation or its equiv
-alent. In addition, hydrogen fluoride oifers the l
further advantage that, since itis quite stable
and has a normal boiling point'of> `19.4" C., it can
be distilledV at ordinary temperatures and pres
Isuresyvithout decomposition. Therefore, the hy
drogen fluoride` catalyst can be easily and cheaply
puriiied as often as necessary by a simple distilla
tion procedure whereby it may bevreused indeli
While the amount of either high- or low-,boiling
ably should not exceed about ñfty mol percent,
with some of the more active catalysts, or Where
' the extent of reforming desired is small, some
what larger amounts of added hydrocarbons may
be present. In the case of aluminum chloride,
for example, amounts up to 200 mol percent of
isobutane may be added, and in some cases'such
a large addition might be desirable to enable bet
ter control of the extent of the reforming reac
tion.
Without attempting to theorize as to the me
chanics of the reaction by which a hexane, hep
~ tane or an octane, for example, reacts to form
isobutane, isopentane, hexanes, etc., up to 10„to
12 carbon atom saturated hydrocarbons, I have
found that the presence of a low-boiling isopar
nitelyin my process. Hydrogen iluoride presents
affin, such as isobutane or isopentane, or a high
other‘advantages over sulfuric acid because of »its
‘lack’ of oxidizing effect-upon hydrocarbons per- „I-Ó boiling hydrocarbon, such as a decane, tends to
mitting use at high temperatureswithoutdanger
suppress the reaction towards the formation of
these lower and higher boiling products. The
of oxidizing the reactants', and low density land
viscosity permitting relativelyV small expense for
agitaticn‘and admixture ofÍ the catalyst and hy'
Èdrocarbon inimiscible layers-:4" f1 Y' ï»
result is the formation of a higher percentage of
intermediate boiling products, and a slowing
downof there'a'ction.’
'
-
’
'
agoaeae
8
7
As stated previously, the high- and low-boiling
cycling these fractions to the reforming reactor.
alkylate charge stock, a simple andnovel com
bined process is possible »by using the same al
kylation catalyst for the reforming step as was
used` for the alkylation. In such a process, it is
unnecessaryy to remove the alkylation catalyst
from the alkylate product-containing, reaction
mixture. Since it is usual to conduct alkylation
Normally, less than 40 mol percent of the nar
reactions with the use of a large excess of iso
fractions may be combined andwill react to
gether in the presence of an alkylation catalyst
under alkylating conditions of temperature and
pressure to form additional gasoline-boiling ma
terial. This may advantageously be done by re
row-boiling feed is reformed to material boiling
parafûn, this isoparafiìn should either be re
outside of the gasoline range, even in the absence 1,0 moved,V or, where its presence to influence the
of added high- or low-boiling material. Since
boiling range of the product is desirable, it may
the rate of recombination of this recirculated
be necessary to only remove a part of it. In any
material is generally at least as rapid as the rate
event excess isoparaiîin must be removed to an
of production of these high- and low-boiling
extent which will allow the reforming reaction
materials from the narrow-boiling. feed, the total 15 to proceed. The excess isoparai‘lin should be
molar ratio of the high-.- and low-boiling hydro
reduced to less than 200 mol percent of the alkyl
carbons to the narrow-boiling fraction in the
ate product, and preferably to less than 100 mol
reaction zone is less than 1 to l. >In some cases
percent of the alkylate. The product-catalyst
Where the reforming reaction yields` substantial
mixture is reformed in the manner heretofore
amounts of high- and low-boiling material, of 20 described by further agitation and contacting
the order of 30 to about 5I) mol percent, and/or
before separation. Therefore, another feature of
the recombination of the recirculated highn and
my invention is a combined alkylation and re
low-boiling feed material is slow, Vrelative to its
forming operation. In such a combined process
rate of formation from the narrow-‘boiling feed,
where excess isobutane, or other lightisoparaiiin
the amount of the high- and low-boiling material 25 is 'formed in the reforming step as described pre
recirculated Will be larger than the amount of
viously, this light isoparanin may be used in the
narrow-boiling fraction fed to the reaction zone.
alkylation step tofmake additional narrow
In such a case Ythe total molar ratio of >the recir
boiling alkylate. My invention is not `to be con
culated hydrocarbons will exceed l to l.. While
strued, howeveizras limited to the use of the
this slows down the reforming of the narrow
boiling fraction, since gasoline-boiling material
is being formedffroml the high- and low-boiling
material, the overall result is the same; i. e., the
30 same >catalyst for the reforming as Was used for
the' preparation of the initial alkylate charge
stock.
‘
In FigureY l of the drawings there is shown
formation Vof a material boiling over the entire,
diagrammatically a complete set up for both
or a desired- portion of the entire, gasoline range. 35 alkylating and reforming, »wherein hydrogen
In some casesit is possible that the amount of
fluoride is-the catalyst used in Iboth steps. In
low-boiling material formed maybe much in ex
this operation a suitable isoparafûn, such as iso
cess of the amount of high-boiling material. If
butane, is fed through line I, provided with con
this is true, and if >the amount of this excess low
trol Valve `2, to a mixing chamber ; 3, wherein
boiling material (principally isobutane) is large 40 it is mixed with an olefin, such as propylene in
‘relative to the amount of narrow-boiling hydro
troduced through line Il, provided with control
carbonbeing processed, -it may be necessary to
valve 5. This mixture is then fed to reactor 6,
withdrawsome of this isobutane from` the proc
in which a stream. of concentrated hydrofluoric
ess. In other words. where mol quantities of
acid -flows counter current to the hydrocarbon
these recycled hydrocarbons are unequal, »the mol 45 charge. This Aacid is recycled from the bottom
excess of the one present in the greater amount
of alkylator 6, to the top thereof through line
should not exceed about 100 to 200 mol percent
l,y by means of pump 8. The alkylate, principally
(depending upon the catalyst being used) of the
heptanes‘ along with unreacted isobutane and
narrow-boiling hydrocarbon *being` processed. In
some entrained acid passes from the top of the
the case of this addition of high- and low-boiling .50 alkylator through. line 9, to settling tank I0,
hydrocarbons, the high-boiling and low-boiling
Wherein‘the hydrocarbons and acid separate to
materials probably react with the branched-chain
two layers. vThe acid leaves the bottom of this
hydrocarbon being processed-as well as with
settling‘tank through Aline II and is‘returned to
each other. This same reaction between the
the alkylator along with the recycled acid pass
reactant hydrocarbon being processed and recy 55 ing through line 1. The hydrocarbons flow from
cled hydrocarbon or any added saturated i'sopar
aiiin undoubtedly occurs where only a single ad
ditionalV component is present. The exact me
chanics .of the reaction occurring in a two or
the settling tank through line I2, to fractionator
I3, provided with suitable heating coil I4, where
in the isobutane isl removed from the alkylate
as` overhead through line I5. Suitable means
60 (not shown) are provided for returning some iso
vention is not to be considered as bound to any
butane to the'fractionatcr as reflux. The alkyl
theoretical consideration. The manner in which
ateproduct
from the bottom of this fractionator
these added hydrocarbons affect the reaction is
flows _through line IG, provided with pump Il,
immaterial. The resulty is that `the catalyt‘i‘c're
, more component System is not clear, and my in
arrangement favors the formation'of less hydro
carbons boiling above and below the gasoline
range. >Where onlylone type of hydrocarbon is
added, the.`material to be reformed should con
stitute at least 35 to 50 molv percent of the total
mixture. Asa consequence ofthe. e?îectfof _these
added hydrocarbons, a simple procedure for con
to reformer I8. In this reformer, as in the al
kylator, a stream of concentrated hydrofluorlc
acid _flows counter current to the hydrocarbon
charge.l lI‘he reformed hydrocarbons pass throughy
line I9,-to settling tank’ 20„vvherein the mixture
hydrocarbons and entrained acidseparate into
7,0 of
two layers in the manner previously described.
trolling and regulating the distillation character
The acid being recycled passes from the .bottom
istics of .the finall product is available.,-
of> the` reformer through line 2|, provided with
pumps-x22, tothe top thereof. The acid layer
from the settling tank 20, is `»returned to the lbull:
, _
Y Inasmuch as my process involves theuse vof an
alkylation catalyst for the> _treatment of an
2,403,929'>
oftheV recycled acid in line 2|, through line 23.
The hydrocarbons from the settling tank 20, flow
by -line 24, to fractionator 25, provided with a
suitable heating coil 26, wherein isobutane along
Gasoline
Original
fraction
alkylate (25°-160° C )
of reformed
product
with small amounts of isopentane are removed
byi fractional distillation overhead through line
Octane rating, A. S. T. M. method:
21. Means (not shown) are provided for re
»
-
Y
No TEL ____________________________ _.
fluxing part of the fractionator overhead. The
69. 9
`
.
74.8
83
'
88.9
'85
-
92.3
overhead from the fractionators in lines I5 and
21, are combined in line 28, and returned to the
isobutane feed line I. lIfhis line 28 is provided
with a suitable pump 29. The bottoms from the
G9. 2
73. 4
, 79.8
84.4
fractionator pass through lineal), provided with
> 185
pump 3|, to scrubber 32, wherein the last traces
of hydrogen fluoride are removed by washing
with an aqueous alkaline solution circulating
L’
.,
F ............. _.f'. ____________ __
Reid vapor pressure at 100° F ___________ ,_
through line 33, provided with pump v34. The
scrubbed product ñows through line 35, to
-
88.6
91.8
172
,_ 105
137
190
192m
` v‘182
_ 201
199
Y
222
>208
"310
4. 5
_ 6.9
It will be noted that the gasoline-boiling.frac-U
stabilizer 36, where the gasoline fraction is re
moved by distillation through line 31, as an over 20 tion of the reformed product meets thedistilla.
tion Aand vapor pressure requirements for aviation
head product. The stabilizer is provided with a
gasoline and has an unleaded octane number al
suitable heating coil 38, and means (not shown)
most 5 points higher than the original4 alkylate.
are provided for reñuxing part of the overhead.
It possesses the same high lead susceptibility as
The bottoms from the stabilizer are fed back
- `
.
through line 39, either to the mixing chamber 25 the original alkylate, i. e., about 2.1. .
The gaseous by-product distilling-below` 25° C.
via line 49, or to the reformer via line 4 I, where
was composed entirely of isobutane, and was re
in these bottoms are reacted in' the presence of
acted with the fraction distilling above 160° C.
concentrated hydroñuoric acid and the lighter
to producean additional quantity of aviation boil
isoparaiiîns to give additional quantities of gaso
line-boiling range material. Valves 42 and 43 30 ingrange gasoline. To illustrate the procedure
for doing this the fraction distilling above 150°_C.,
are provided with lines 40 and 4l, respectively,
which amounted to 439 parts by weight, „was
whereby the distribution of the return of the
mixed thoroughly with 300 parts by weight of
stabilized bottoms may be controlled. Line y44 is
provided so that a suitable portion of the over
head from fractionator 25 may be recycled di
isobutane and 240 parts by weight of anhydrous
aluminumy chloride for 7 hoursatroomtempera~
rectly to> the reformer, although these light iso
ture in a steel autoclave. ' During this time a
gradual pressure drop from about29 to about 21
paraffins may also 'be obtained in the reformer
pounds per square inch (gage) took placer. `In
by regulating the amount of excess light iso
this reaction there wasa pressure drop sincethe
parafûn taken overhead from the fractionator
I3. Valves 45 and 46 are provided for controlling 40 the reaction products normally havea lesser vapor
pressure than the original high- and low-boiling
the distribution of the overhead from fraction
fractions. As in the previous ease, this change
ator 25.
in the pressure was used as a measure ofthe ex-V
The following speciñc examples of >operation
tent of reaction. Agitationwas then.- discon
are given to further illustrate the principles of
my invention and the advantages obtained by 45 tinued, the hydrocarbon phase separatedffrom
the catalyst, and the gasoline fraction distilling
my process. These examples are illustrative
in the range 25° to 160° C. recovered as inthe
only, and are not to be `construed as limiting
previous case. .This fractionamounted Vto., over
the scope of my invention to the details set forth
60 percent by weight of the total product and
therein.
~
50 had approximately the same composition as the
Example I
corresponding fraction obtained by catalytic` re
A_n alkylate charge stock composed principally
forming of the original alkylate.
-.
l
-
.
.
,
_ ,
parts by Weight produced by the reaction of iso
By repeatedly reacting the light ends with the
heavy ends and removing the gasoline range
oughly with 1350 parts by'weight of anhydrous
gasoline of high octane rating which meetsthe
of branched-chain heptanes in an amount of 4290
pentane with ethylene in the presence of an 55 material by fractionation, therefore; substantially
all of the original alkylate can- be converted to
hydrous aluminum chloride, was mixed thor..
distillation and vapor pressure requirementsv for
aviation gasoline. The continuous recycling pro
gradual pressure rise from about l to about 8 60 cedure already described is, of course, preferable
for carrying out this process on a commercial
pounds per square inch (gage) took place. This
aluminum chloride for 7 hours at room tempera
ture in a steel autoclave.
During this time a
scale.
pressure rise was caused by the formation of pro
portionately larger amounts of light isoparafñns
having normally a higher vapor pressure than the 65
alkylate charge stock, and was used as a measure
of the extent ofreaction. - Agitation was then
discontinued and the hydrocarbon phase sepa
l
.
Example II
_
1380 parts by weight of alkylate' (principally
branched-chain >octanes), having an octane nurn
ber by the A. S. T. M_ method of 93, produced by
reaction of i'sobutane with normal butene in the
presence of concentrated hydroiluoric acid, were
rated from the catalyst, washed with water, and
dried over .anhydrous calcium chloride. The dried 70 mixed thoroughly with 1328 parts by weight of
hydrocarbons were then fractionated to recover
hydrofluoric acid for 15 hours at room tempera
the gasoline distilling in the range 25° to 160° C.
ture in a steel autoclave to obtain substantially
f The properties of this fraction and the original
complete reforming of this alkylate. During this
alkylate are given in the following table for com
time a gradual pressure rise from about 23- to
parison:
.
*Y
f
.
7.5 about 27 pounds per square inch (gage) « took
2,403,929
11
12
place, which was used as a measure of the extent
of reaction. Affitation was then discontinued and
tent of reforming in this experiment fell midway
between that obtained in the two previous exam
ples as shown by the distillation curve, D, of the
the two liquid phases, i. e., the hydrocarbon phase
and the hydroiiuoric acid phase, allowed to sepa
liquid product boiling above isopentane in Fig
rate. Thehydroñuoric acid phase was withdrawn
ure 2.
as the bottom layer and the hydrocarbon phase
The following examples were performed to show
washed with water, dried over anhydrous calcium
the effect of an added hydrocarbon, boiling out
side the gasoline range on the reforming process.
chloride, and fractionated to recover the gasoline
distilling in the range 25° to 168° C.
Example VI
The gaseous by-prcduct distilling below 25° C.
The experiment described in Example IV was
was composed entirely of isobutane, and was re
repeated except that 46.5 mol percent of isobutane
acted with the fraction distilling above „168° C.
was added to the alkylate charge before contact
to produce an additional quantity of gasoline
ing it with the acid for 14 hours. The extent of
boiling range material. To illustrate the proce
dure for doing this the fraction distilling above 15 reforming in this experiment was appreciably
less than that obtained in* the absence of iso
168° C. which amounted to 317 parts by weight
butane as shown by the distillation curve, E, of
was mixed thoroughly with 216 parts by weight
the liquid product in Figure 2.
'
of isobutane and 447 parts by weight of concen
trated hydrofluoric acid for 9 hours at room tem
Enample VII
perature in a steel autoclave. During this time 20
The experiment in Example III was repeated
a gradual pressure drop from about 40 to about
except that 104Y mol percent of isobutane was
35 pounds per square inch (gage) took place
added to the alkylate charge before contacting
which, as in the previous cases, was used as a
it with the acid for 24 hours. Distillation curve
measure of the extent of reaction. Agitation was
then discontinued, the two liquid phases sepa 25 F in Figure 2 shows the extent of the reforming
obtained in this experiment.
rated, and the hydrocarbon phase fractionated
As mentioned above, the distillation curves for
as before to recover the gasoline fraction dis
the products of Examples III to VII boiling above
tilling in the range 25° to 168° C.
isopentane Yhave been plotted in Figure 2. This
The properties of the composite gasoline pre
pared in this manner are given in the following 30 graph, wherein volume percent of gasoline-boil
ing material distilled is plotted againstV distilla
table:
tion temperature, effectively illustrates the utility
of my invention. For comparison purposes, the
distillation curve of the original heptane fraction
Plus 3 cc.
No TEL
TEL/gallon
k35
Octane rating:
A. S. T. M. method_._
84. 2
100. 0
Research ’39 method. _
83. 3
97.3
A. B. T. M. distillation:
50%
70%
90%
Temperature, °F .... ._ 126
223
247
272
E. P.
320
propylene is shown as curve A. This curve shows
that this heptane alkylate has a narrow-boiling
range between 80 and 100° C.
By a comparison of curve A with curves B, C,
l
Vol. per cent distilled__ 10%
obtained by the` alkylation of isobutane with
40 and D, the effect of the reforming reaction on
the'boiling range of the alkylate fraction may
be readily seen. Approximately 85 percent of
the product boiling above isopentane distilled
rather uniformly over the entire gasoline range.
The lower-boiling material, not shown in the
curves, constituted about 30 percent of the orig
inal heptane fraction, and was about equally
divided between isobutane’and isopentane. The
isopentane fraction is, of course, suitable for use
Reid vapor pressure at
100° F _____________________________ __ 8 pounds per square inch
It Will be noted that this product has an A. S.
T. M. octane number of 100 with only 3 cc. of
tetraethyl lead per gallon. Substantially com
plete reforming was obtained in this case as shown
by the high vapor pressure and the appreciable
quantity of low- and high-boiling hydrocarbons.
Example III
50 in gasoline, so about a total of 70 percent of the
original heptane fraction was recovered directly
19.7 parts by? weight of alkylate (principally
as a gasoline fraction ofW uniform distillation
branched-chain heptanes) , produced by reaction
characteristics over the entire gasoline boiling
of isobutane with propylene in the presence of
range.
concentrated hydroiiuoric acid, were mixed thor
Curves B, C, and D show the effect of time upon
oughly with 26 parts by weight of concentrated 55
the reaction. The extent of reforming is sub
hydrofluoric acid for 24 hours at room tempera
stantially the same over the entire time range of
ture. The liquid product from this reaction was
4 to 24 hours. Curve B shows that somewhat
recovered as in Example II. Substantially com
more reforming was obtained at 24 hours than at
plete reforming was obtained as shown by the
distillation curve, B, of the portion of the product 60 14 hours shown in curve C. Where the reform
ing reaction was allowed to proceed for only 4
boiling above isopentane in Figure 2.
hours, substantially the same degree of reforming
Example IV
was obtained by slightly increasing the amount
The experiment described in Example III was
of catalyst used, as shown by curve D lying in
repeated except that the time of contact between 65 termediate curves B andk C.
the hydrofluoric acid and the _alkylate was 14
A comparison of curves C and E shows the effect
hours. The distillation curve, C, of the liquid
of an added hydrocarbon boiling outside the gaso-Y
product boiling above isopentane is given in Fig
ure 2.
Eâllample V
line range on the process.
The effect of the
added hydrocarbon, isobutane, was to increase
70 the proportion of intermediate boiling material'.
The experiment described in Example III was
repeated except that a larger weight ratio of
catalyst to alkylate was employed, i. e., 1.56 in
stead of 1.32, andthe time of contact between
catalyst and alkylate was only 4 hours. The ex 75
In the presence of isobutane (46.5 mol precent)
over 65 percent of the material boiling above
isopentane boiled within the range from 60 to 120°
C. In the absence of isobutane only about 45
percent of the material boiling above isopentane
2,403,929
14
13
to be understood narrow-boiling, branched-chain
hydrocarbon fractions in general may be used.
For instance, such a product formed by polymer
izing oleñns and then hydrogenating the poly
boiled in this same range. The amount of mate
rial boiling above the gasoline range was less than
l0 percent, as compared with about 15 percent
in the case of reforming in the absence of iso
butane. The amount of total low-boiling mate
rial, not shown on the graph, was also consider
mers could serve as a stock to be reformed.
Many modifications of my invention will be
apparent to those skilled in the art, and only
ably less, making the total gasoline-‘boiling mate
rial, including isopentane, about 85 percent.
such limitations should be imposed as are indi
cated in the appended claims.
Curve F shows that where the amount of iso
I claim:
butane added, in the case of the hydrofluoric acid 10
1. The process which comprises contacting a
catalyst, exceeded an equimolar quantity the re
mixture of an isoparaûin and an olefin in which
forming reaction was almost completely sup
the mol ratio of the isoparaifln to the oleñn is
pressed. The reaction was allowed to proceed for
greater than two to one with an alkylation cata
24 hours, and the curve shows that in the pres
ence of such a large amount of isobutane, an ex
cessively long time would be required to obtain
15
lyst consisting essentially of hydrofluoric acid
under alkylating conditions of temperature and
pressure for said catalyst to form a relatively
narrow-boiling alkylate, separating at least a suf
The curves show that in the absence of added
ficient amount of the isoparai’n‘n from the hydro
isobutane, the contact time may be varied from
about one hour to about 24 hours without appre 20 carbon product mixture to reduce the isoparaf?n
alkylate mol ratio to less than one to one, con
ciably altering the results. 'I'his is evidence that
tacting the alkylate product containing less than
with an active catalyst equilibrium is established
one mol of isoparaflin per mol of alkylate with
in the system in a comparatively short time. In
an alkylation catalyst consisting essentially of
case it is desired that the major fraction of the
hydroñuoric acid under alkylating conditions of
reformed product boil over but a limited portion
temperature and pressure to reform said alkylate
of the gasoline range, contact times of less than
to higher and lower boiling saturated hydrocar
about one hour may be used, the concentration
bons, allowing the hydrocarbons and catalyst to
of the catalyst may be lowered, or a low- or high
remain in contact until the desired amount of
boiling hydrocarbon added.
appreciable reforming.
It is important to note that the reformed prod
uct obtained by my process is not a low octane
30
product as might be expected, but rather it hasY
an octane rating that compares favorably with
that of the original alkylate and is frequently
higher than that of the original alkylate. When
dealing with a narrow-boiling, branched-chain
the original narrow-boiling fraction has been re
formed to give a mixture of hydrocarbons whose
boiling range has a desired distribution over the
gasoline boiling range, separating the hydrocar
bons from the hydrofluoric -acid catalyst, frac
tionating the hydrocarbons to remove saturated
hydrocarbons boiling below and saturated hydro
carbons boiling above the desired range, returning
fraction of relatively low octane number, such as
the hydrocarbons so separated in admixture for
the ordinary heptane alkylates, the octane num
further contacting with the alkylation catalyst,
ber is raised in addition to obtaining a desired
spread in the boiling range. Some of the al 40 and recovering the desired hydrocarbon fraction
kylates, such as the isobutane-butylene alkylate
of controlled-boiling characteristics.
2. The process which comprises contacting a
of Example II, which have a very high octane
mixture of an isoparaflin and an olefin in which
number, will give a somewhat lower octane rating
the mol ratio of isoparailin to the olefin is greater
for the reformed product. The reformed prod
uct, however, might easily have a higher octane 45 than 2 to 1 with an alkylating catalyst consisting
rating than the motor fuel obtained by blending
the high octane alkylate with the blending agents
available and capable of giving the alkylate the
proper boiling characteristics.
Also a partial re
forming of a high octane alkylate so that it may I
be blended with available blending agents to give
a complete motor fuel may frequently be desirable,
and such a partial reforming could be accom
plished at a lesser sacriñce of octane number. The
improvement in the boiling characteristics of the
alkylate will frequently be desirable and necessary
for the effective utilization of a particular al
kylate, and for the production of a high octane
complete fuel. The process is therefore of value
for the treatment of high octane alkylates as well
as the lower octane alkylates, even though with
the former there is some sacriñce in the octane
number of the alkylate itself. The octane rating
of my reformed products may be easily brought
up to aviation requirements by the addition of
small and permissible amounts of tetraethyl lead.
It is also important to note that my process is
capable of producing a complete gasoline, and
that in so doing, a larger percentage of the al
kylate, and hence a larger percentage of gaseous
hydrocarbons going into alkylate, will be repre
sented in the finished product.
The invention has been described with particu
lar reference to alkylate gasolines; however, it is
essentially of hydrofluoric acid under alkylating
conditions of temperature and pressure for said
catalyst to form a relatively narrow-boiling al
kylate, separating a suiiicient amount of isopar
ai-lin from the hydrocarbon product mixture to
reduce the isoparaffin-alkylate mol ratio to less
than 1 to 2 contacting the alkylate product con
taining less than one-half mol of isoparaflin per
mol of alkylate product with an alkylation cata
lyst consisting essentially of hydrofluoric acid
under alkylating conditions of temperature and
pressure to reform said alkylate to higher and
lower boiling saturated hydrocarbons, allowing
the hydrocarbons and catalyst to remain in con
tact until the desired amount of the original
narrow-boiling fraction has been reformed to
give a mixture of hydrocarbons whose boiling
range has a desired distribution over the gasoline
boiling range, separating the hydrocarbons from
the hydroñuoric acid catalyst, fractionating the
hydrocarbons to remove saturated hydrocarbons
boiling below and saturated hydrocarbons boiling
above the desired range, returning the hydrocar
bons so separated in admixture for further con
tacting with the alkylation catalyst, and recover
ing the desired hydrocarbon fraction of controlled
boiling characteristics.
CARL S. KUHN, JR.
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